Treatment of plant growths



' be set forth in part hereinafter and in part will Patented Jan. 27,1942' UNITED STATES PATENT. OFFICE I 2,271,212 v No Drawing. ApplicationJanuary'11, 1940, 8e-

rial No. 313,343. In Canada March 9, 193'! 5 Claims. (o 21-50) timberwith, carbohydrate solutions which penetrate the cells of the timber,displacing the natural liquid and fermentabie constituents andintroducing agents which act as preservatives and to stabilize andotherwise affect the: wood.

Objects and advantages ofthe invention will be obvious herefrom, or maybe learned by practice with the invention, the same being realized andattained by means of the instrumentalities and combinations pointed outin the appended claims.

The invention consists in thenovel parts, con

'structions, arrangements, combinations and improvements' hereindescribed.

This application is /a continuation in part of.

ment of freshly felled green timber in log form,

preferably with the bark still on the log and with the" natural saps,extraneous matters, resins. Juices and other liquid and volatilecomponents of, the living tree still present and unchanged in the wood.The invention comprises certain novel steps and technique and alsocertain novel combinations and solutions of ingredients where'- bypreservative and wood-penetrating materials, whichheretofore have beenintroduced into the wood only by the immersion process, and even thenunsatisfactorily, may be. introduced with much greater-rapidity andmoreeffectively di's-.

tributed through the wood by endwise or axial penetration of theunbarked log. 2

In previously known processes, attempts at preservation .and otherpreparation of timber have been made by the use of solutionscom.

taining true. or more sugar materials which are known to penetrate thecellsof the wood and displace the natural contents thereof by osmoticaction.) The action on wood of the sugar soluwood fibers and cells aredisplaced by a carbohydrate, particularly one of the sugars. Heretoforetreatment of wood with such sugar solutions,

has been attempted by the immersion process; that is, marked logs orsawn lumber boards were submerged in a tank containing the sugarsolution' and penetration of the wood was eflected by a prolongedcooking action in which the solution was raised to a high temperature,and usually to the boiling point. By gradually raising the temperatureand carrying out the treatment over several hours a fairly satisfactorypenetration of -the wood by the carbohydrate solution was eflected.However, the-rate and extent of penetration depend upon the thickness ofthe board as well as the time of treatment as the solution enters fromall surfaces of the immersed wood, and the cost, time consumption andnon-uniform results have prevented successful commercial exploitation ofsuch solutions with the immersion process.

The present invention eifects much more complete, rapid and uniformpenetration of the wood cells and fibers by sugar solutions, causing thetreating materials to penetrate and travel rapidly and thoroughly fromone'end to the other of a freshly felled log. Such axial application andpenetration of sugar solutions has never been successfully practicedheretofore and aprimary object of the invention is to render such use ofsugar solutions commercially practicable and more eflective and cheaperthan methods previously used with such solutions. Whereas in the priormethods of applying sugar solutions to wood by immersion, all surfacesof the wood were simultaneously subjected to the penetrating action ofthe-solution, in the present invention,

the solution enters at one end only of the log,

the opposite end being left free and at atmospheric pressure. Hence thesolution enters the log rapidly without opp sition from counterpressuresof solution entering at other points and thereby the full benefit of thepeculiar penetratin'g action of 'the sugar solution may be en- Joyed. Bythe present process the. penetration and distribution of the treatingmaterials is very rapid and far more thorough than any prior process;moreover, the treatment is carried out at temperatures substantiallythose of the log itself and without any boiling or cooking action, sothat weakening and changing of the wood ilbers by high'temperaturesisavoided. The log tions in general is known tozbe that'of asimilaracting on a similar wherein the. natural sugar solutions and otherfermentable contents of the t6 -rectly immediately to requires andreceives no preparation prior to the treatment as the treatingflution isapplied ,di-

e nd 1 e 0 a freshly able substances of the wood automatically issue 3from one end of the log as they are displaced by the entry of thetreating solution at the other.

.Said extractive materials are removed in their natural'state andunaffected by high temperatures or chemical action.

As will be clear, one object of the invention is to improve and speed upthe operation of the socalled Boucherie method of wood impregnation.While the present invention is similar in its physical technique to thatof the Boucherie process of end-for-end log impregnation, the rapidityand thoroughness of penetration of the log by my invention are manytimes greater than that effected by the Boucherie method.

Another object of the invention is to utilize sugar solutions of muchlower concentrations than those heretofore used in the art. Whereas inthe prior practice of impregnation of wood by sugar solutions throughimmersion, it'has been customary to use sugar solutions of the order ofof sugar or higher, the present invention will achieve many of itsbeneficial effects by use of a very low concentration of sugar on theorder of 5% and as low as in some cases. Moreover, by using theend-for-end technique of impregnation, the distribution of the lowconcentration sugar solution is virtually uniform radially of the log,whereas in theimmersion process, a much higher concentration of sugar isfound at the surface than at the interior of the tion but notrestrictive thereof. 7

Referring now in detail to the present preferred embodiment of the,invention, the process and solutions used therewith are preferablyapplied to thebutt end of a freshly felled green log, from which thebark has 'not been removed and the cambium or inner bark is preferablyintact. By freshly felled it is intended to define a log in which thenatural sugars and other protoplasmic substances have not becomecrystallized or hardened by drying. Thus logs may be treated at aconsiderable time after they have been ielledprovided drying and thenatural crystallization effect'has not progressed to the point whereosmotic penetration of the cell walls has become impossible or greatlyimpaired. Such drying may be prevented for a; considerable time bymaintaining the log in a pond or moist atmosphere.

The treating solutions used with the present process are of thety'pehaving a sugar base, and one which-has the natural capacity ofentering into the cells and fibers of the wood by osmotic action; Thenature, constituency and action of such solutions will be detailedhereinafter. 'In

the process a solution of the nature indicated is applied to one end(preferably the butt) of the fresh log and a supply thereof ismaintained against-said end while the solution enters and travelsthroughout the length of the log. The

entry and travel of the solution through the log is facilitatedbysupplying the solution at the exposed end of the log under arelatively low hydraulic pressure, the usual pressure being about fiveor six pounds per square inch and rarely exceeding forty. In practicethe solution is confined about the treated end of the log by a hollowcap or header which fits tightly over the end of the log, beinghermetically sealed thereto by a suitable gasket. The bark is preferablyremoved near the end and the woodmay be smoothed or chamfered to providean even fit for the gasket and header. The opposite face of the cap orheader is connected by a pipe or hose to a source of the solution underpressure, a pump or the like of controllable capacity being preferablyused in practice. Apparatus of the general type described is well knownin the art cylinder of the ring growth of the tree appears to transmitthe solution more or less independently of the others, there beinglittle or no radial circulation therebetween; Also the solution acts tolubricate or partially dissolve the bond between the cambium and bark asthe latter can be very readily removed after treatment by a simplepeeling operation.

As the solution enters and travels through the log it displaces ahead ofit the sap and other liquid and soluble constituents of the tree andthese extractive materials flow from the opposite end of the log wherethey may. be collected and utilized as desired. Liquid or moisture isnaturally held in the wood in two distinct waysimbibed moisture" in andaround the walls of the ,W00d 08 1LS and freemoisture within the cellcavities including the vacuoles and protoplasm. When green wood driesout naturally, the free moisture leaves first, followed by the imbibedmoisture. In order to secure a more suitable and stable fiber saturationpoint inwood the present process removes the free. moisture from thecells and replaces same with the preservative solution which shortlysolidifies preventing further absorption into the cells. By thereplacement of natural moisture or sap in wood with sugar solution,which with other chemicals acts to dehydrate the wood structure from theinside outwards and perform other desired results including thepermanent stabilizing of the contents, the invention practicallyeliminates shrinkage and swelling or dimensional changes. The sugarsolution has the capacity of penetrating (possibly by osmosis) into the-cells and into the vacuoles and 'protoplasm within the cells anddisplacing the cell sap, organic acids and mineral matter, known as"free moisture or cell cavity water. Also said solution, in travelingthrough the tree, displaces and flushes outthe imbibed moisture whichlies around and between the cell walls. Thus by this removal of imbibedand free moisture because of the chemical reaction of the solution used,the cellulose or wood structure be- 1 comes cleansed of the minor orextraneous components in the wood such as resins, terpenes, fats,nitrogenous organic compounds, tannins, pigments, mineral matter,and'the organic acids,

which all exude from the end of the log opposite to the end at which thesolution is supplied. Thus, besides thoroughly cleansing the log, thestructure is filled with the solution which performs various functionsas desired, depending upon the chemical mixtures used. Such chemicalsgain entry into the fiber and cellular structures of the wood throughthe base sugar solution acting as a vehicle or carrier whereby they arepermanently deposited to stabilize, color, fiameproof, or prevent insectattack by toxic agents.

The treatment of the wood with sugaras described has been found toresult in a notable incrystallize on the cell wall thereby increasingits structural strength. This increase in strength of the cell wall notonly improves the natural strength qualitiesof the wood, but apparentlyis responsible at least in part for the anti-shrink effect, as the sugarsubstance is non-volatile and therefore tends to prevent collapse of thecell walls during drying and after the moisture content has been reducedbelow the critical point, i. e., the elimination of the free moisture.Many of the phenomena exhibited bytheaction of the sugar in entering thelog and the characteristics solution travel or flow through the wood ismaterially reduced and eventually almost stops. As

the wooditself becomes heated at thetreatedend, the fibers swell and thewood attains a congested condition. 1

. Referring now to the preferred constituents and characteristics of thesolutions used in penetrating and treating the wood, the processutilizes the known effect of carbohydrate solutions, par- 10 ticularlythe sugars, to penetrate and occupy the wood cells and fibers. Moreparticularly, these sugars or sugar substances which have a. lowmolecular weight and high aptitude for penetrating the wood cells arepreferred. Examples of such effective sugars are the mono-saccharides,

such as corn dextrose, commercially known'as 1 hydrol, although sucrosesand other di-saccharides may be used-in some cases.

It is diflicult to generalize very far because the '20 preferred sugarvaries considerably with respect to the species of wood treated, thekind of treatment and the results desired. The pH of the solutionalsovaries. For example, in impregnation of chemicals for the purpose ofpreservation the solution should be on the acid side, while forpreparation ofthe wood for pulping or impregnation with dyes, analkaline reaction is "preferable.

The following is a classification of sugars/in order'of preference,indicated-by my present experience, but is not restrictive of'theinvention:

Com sugars A. The substance which gives the most rapid f the wood afterbeing so treated indicate that penetration (the greatest promoter ofosmosis or the sugar molecule (glucose or other mono-saccharidemolecule) is adsorbed by the cellulose molecule of the wood.

For ordinary purposes or preservation, stabilization, coloring or thelike treatment of the wood, introduction of the solution at the-treatedend is maintained until specific gravity tests of the liquid issuing atthe free end indicate that the treating solution is issuing therefrom,at full strength.

It has been found in practice that proper control and maintenance of thetemperature of the treating solution in fairly definite relation to thetemperature of the interior of the-log itself is one of the essentialcharacteristics of the present process. The temperature of the solutionshould be 'near or slightly higher than that of the interior temperatureof the logitself. For example, in treating logs having an interiortemperature of approximately 60 degrees F., theatmos phere being about80 degrees F., a solution temperature of between 80 and 90 degrees R wasfound very effective. In general it may be stated that the temperatureof the solution should be substantially above 40 degrees F. and rarely,if ever, at temperatures substantially higher than said temperatures andpressures being regulated according to the results desired and theparticular wood being treated. At'the lower temperatures the sugars andother materials in solution tend to solidify or thicken, while thehigher temperatures cause swelling and congestion of thea wood cells andfibers, thereby physically impeding penetration and impregnation of theliquidin the wood structure. At temperatures over 120 whatever the woodpenetrating phenomenon may be) is anhydrous or regular cerelose, a corndextrose. The anhydrous runs 99.8% dextrose, with no mineral content,and .2% water. The regular cerelose is 91.5% dextrose, .5% mineral, andabout 8% water. Cerelose, however, lacks the desired wood stabilizingqualities (i. e., prevention of shrinking, warping, etc).

B.For general all-around eifectiveness a 70% ,PCOID. sugar is best. Thissugar comprises 70% dextrose'with .85%,mineral substance. It may run-to17.75% moisture. I

C. Hydrol is the best I have found for general results and 'low price.During the last few years cgmmercial hydrol has varied considerably indextrose, moisture and ash, which make considerable difference in thiswork. It is also affected by variations in non-reducing and reducingdi-sac-harides, as well as a probable content of about 5%tri-saccharides. I understand that hydrol is taken from the line ofanhydrous and cereal sugars being P ocessed from comto produce' alcoholand fermentation products.

D. Another corn sugar I have tested is corn syrup or glucose. While thishas about 35% dextrose, its high dextrine content (45%) makes itunsuitable. The Baum reading runs about 41-42.

Cane sugars a fair dextrose result, butieven considering their invertcontentof 18%, the ash runs too high 2 (about 14%) organic non-sugars15% and 'a high moisture 0f'24%.

C. South sea island sugars, such as are used in degrees F. it has beenfound in practice that the western Canada, are much better than the Beetsugars Beet molasses (discards) work fairly well but might as well beclassed in the refinery group as being too high in ash and hence toocolloidal in solution. I

I have discovered that, chiefly by maintaining the sugar solution at therelatively normal temperatures indicated above, sugar solutions may becaused to travel with exceeding rapidity through the length of a freshlycut log. For example, in logs of relatively short length up to say 8feet, I can effect a complete end-for-end penetration of the treatingsolution at speeds as high as one lineal foot per minute regardless ofthe diameter of the log. With long logs, the rate of penetration isconsiderably slower because of the natural resistance from internalhydraulic pressures. However, the improvement in speed of penetration onlonger logs as compared with former practice of the Boucherie system inwhich no sugar solution is used, is also surprisingly high. Whereas, inthe Boucheri'e system it is customary to require several hours topenetrate an 8'foot log, I can penetrate the same length log with myprocess in an equal number of minutes; while I can impregnate a 40 footpole in say 5 to 8 hours as compared to an equal number of days in theusual practice of the Boucherie process.

As hereinbefore stated, I have made another important discovery in thatrelatively very low concentrations of sugar in aqueous solutions can beused to penetrate logs rapidly when the logs, temperatures, andpressuresare maintained within the conditions and limits disclosed. Thusan equally rapid and thorough penetration of the solution may beeffected with a solution having a sugar content as low as andan'incre'ase in the sugar concentration beyond that point does notmaterially increase the rapidity and thoroughness of penetration.However, greater quantities of sugar up to say 10% are found to increasethe stabilizing or seasoning effects and also the strengthening of thewood. That is,

by loading higher quantities of sugar into the log, I can increase theanti-shrinkage effect and inhibit warping and checking while at the sametime raising the structural strength of the wood. Thus if it is desiredprimarily to use the sugar solution as a vehicle for thorough and rapidintroduction and impregnation of a preservative agent such as zincchloride or other soluble woodpose I have found aluminum sulphate mostdesirable as it speeds up air seasoning and kiln drying; while impartinga mild toxic and preservative effect to the wood but without anyundesirable effects.

The following formula is given as typical of the ranges of ingredientsused for various purposes, primarily for the stabilization and'seasoningof wood:

- Per cent Sugar From /2 .to Aluminum sulphate From /2 to 5 Boric acidFrom to 5 In general the relative proportions of the matetreating agentssuch as .dyes, toxics or fiameproofing chemicals, sugar solutions as lowas will provide the desired vehicle for introduction and distribution ofthese other chemicals. However, when the primary consideration is thestabilization of the wood and strengthening thereof, higher quantitiesof sugar up to 10% can be used with benefit. For practical seasoningpurposes, an optimum quantity of sugar which willnot be prohibitive incost yet give a high degree of'strengthening, seasoning andstabilization will be a 4 or 5% solution of sugar.

Other ingredients or chemicals may be added to the solution to givevarious effects. As stated, the wood preservatives such as zinc chlorideor other water soluble salt preservatives,'such as Wolman salts, zincmeta-arsenite, chromated rials used will depend on the result desiredand the species of wood being treated, within the general limitsindicated hereinabove.

In the foregoing solution the sugar material may be any one of the typesof sugars hereinbefore referred to and it will be found that one type ofsugar is preferable for one specie of tree, while another sugar ispreferable for some other trees. In the above formula the boric acid isfound to be helpful in. promotingthe osmotic penetration into andthrough the wood and it also acts as a mild preservative or toxic. Thealuminum sulphate is efiective to dehydrate the wood, reducingthehygroscopic tendencies of-the wood and acting in combination with thesugar to absorb cell moisture and cause the tree to dry from theinterior outwardly. It is thereby helpful in obviating kiln drying ofthe wood and preventing case hardening of the cut wood. It is alsoeffective as a flame repellant and as a mild toxic preservative. A

The foregoing formula may be considered typical for general purposes ofimpregnation and wood seasoning and is indicative of the use of sugar inthe solution as a vehicle to introduce preservative materials and otherchemicals. In the same general manner chemicals such as dyes, preferablythe aniline group, flame-proofing chemicals, such as di-ammoniumphosphate, and in general any other water-soluble substances which maybeused to improve the qualities of wood, can be introduced along withthe sugar solution as a vehicle. It will be'understood for the purposesof stabilization and strengthening of the wood per se, a simple solutionof water and sugar will in itself effect those results, while sap stainand fungus growth will be somewhat impeded by the flushing out anddisplacement of the fermentable natural liquids and substitution thereofby the relatively sterile sugar solution. Another type of wood treatingingredient which may be introduced by this method comprises the woodpulping agents and similar materials for the easier production ofcellulose fiber from the wood. 'Ihedetails of such' treatments aredisclosed and claimed in my co-pending application Serial No. 195,961.

A further improvement in the penetrating effects and treatment of thewood may sometimes be eflfected by the inclusion in the saccharide so- Yit has been found that these agents are most helpful in facilitating theformation of the solution especially when dyes or other substancesdiificult to dissolve are incorporated therein.

Among' the wetting agents which have been found especially effective formany phasesor applications of the process are the substances having thetrade namefAlphasol'" or Aerosol, which are esters of sulpho-saturatedand unsaturated aliphatic dicarboxylic acids, the preparation andcomposition thereof being disclosed in United States Patent No.2,028,091 of January Other wetting agents similarly usable are thecompounds having the trade name A eskap which is a mpn'osodiumsulphonatev f butyl phenylphenol; Arisket asulphonated alkylateddiphenyl; and Ariskene which is a s phonated alkylated oxydiphenyl.Another wett agent similarly usable are the Tergitols', which aresolutions of sodium sulphates of the higher synin effecting the solutionand penetration and fixation of dyes or coloring matter in wood. Whenused with basic, vator analine dyes, it brightens the shades andfaster'colors result. Cellosolve increases the solubility of the dye inthe sugar base, and also isefiective in fixing the dye in the wood. Thissubstance is very effective in penerating the most difficult portions ofthe wood cells and thereby acts to carry or lead in the other elementsof. the solution. It also has a solventaction on the resins, gums andother substances in the wood and to some extent on the cellulose itselfthereby improving penetration and also effecting deposition of the dyesand the sugar material itself on the cell wallsand in the fibersof thewood. It is probable that Cellosolve also acts as an emulsifying agentor link between the oils and water, thereby facilitating impregnationand removal of resins, etc.

For the dyeing or coloring of woodin accordance with the invention thefollowing solution has been found effective:

Per cent Sugar I A to 25 Boric a to 5 W tt agent to -1 Dye My, t0 4Cellosolv A, to

If it is desired to render the wood more flexible or improve the ease ofcutting as for veneer manufacture, either tri or diethylene glycol fromone-half percent to 2% may-be added to the above solution. In certaincases to speed up the drying action of the wood aluminum sulphate inquantities from A to 5% may also be added to the foregoing formula.

The invention also comprises the application of the. foregoing generalprinciples to the preparation'of wood for rendering it insect proof bythe impregnation of toxics; and for introducing flameproofingingredients to render the wood Furthermore said principlesv of theinvention may also be applied to preparanon-combustible.

tion of wood for use in the manufacture of pulp or cellulose material,especially by the introduction of materials which act upon theresins'and lignin in the log thereby to obviate or facilitate scribedbut departures may be made therefrom within the scope of theaccompanying claims without departing from the principles of theinvention and without sacrificing its chief advantages. r

What I claim is: a 1. The process of treating wood which co'mprisesapplying to the end of afreshly cut green log a sugar solution havingosmotic action on the wood and causing said solution to travelthroughthe log toward its opposite end while maintaining the temperature of thesolution near that of the interior of the log, said log beingsubstantially at air temperature. 2. The process of treating wood whichcomprises applying to the end ofa freshly cut green log a sugar solutionhaving osmotic action on the wood and causing said solution to travelthrough the log toward its opposite end whfle maintaining thetemperature of the solution be low that which would cause appreciableswelling of the wood fibers and obstruction to penetration of thesolution.

3. The process of treating .wood which comprises applying to the end ofa freshly cut green log a sugar solution having osmotic action on thewood, said solution containing a surface tension depressant whichfacilitates formation of the solution and penetration thereof into andthrough the wood, and causing said solution to travel "through the logtoward the opposite end thereof while maintaining the temperature of thesolution below that which would cause appreciableswelling of the woodfibers.

4. The process of treating wood which comprises applying to the end of afreshly cut green log an aqueous solution of dextrose, said solutioncontaining a wood-preserving ingredient, maintaining the solution at thepoint of application at a temperature substantially no, higher thandegrees F., maintaining a hydrostatic pressure on said solution againstthe end of. the log and causing the solution to travel through the logto the opposite-end thereof, thereby displacing natural moisture fromthe log.

5. The process of treating wood which comprises applying to the end of afreshly cut green log an aqueous solution of monosaccharide sugar, saidsolution containing less than ten percent of said sugar, maintaining thesolution at the point of application at a temperature substantially nohigher than 120 degrees F., maintaining a hydrostatic pressure on saidsolution against the end of the log and causing the solution to travelthrough the log to the opposite end thereof, thereby displacing naturalmoisture from the log.

CHARLES G. TENGER.

